Device for adjusting the blades of ships&#39; propellers



Dec. 14, 1948. E ATTESLANDER 2,456,361

PROPELLERS DEVICE FOR ADJUSTING THE .BLADES OF SHIPS 2 Sheets-Sheet 1 Filed July 15, 1944 9^ f m. M m 4 0 R M w EY B Dec. 14, 1948. E. ATTESLANDER 2,456,361

DEVICE FOR ADJUSTING THE BLADES 0F SHIPS' PROPELLERS Filed .July 15, 1944 z sheets-sheet 2 QW' CDM-Q M "CLM ATTORNEYS Patented Dec. 14, 1948 DEVICE FOR ADJUSTING THE BLADES 0F SHIPS PROPELLERS Edouard Atteslander, Winterthur, Switzerland, assignor to Sulzer Frres, Socit Anonym Winterthur, Switzerland Application July 15, 1944, Serial No. 545,179

In Switzerland August 14, 1943 3 Claims. (Cl. 170-160.32)

The invention relates to a device for adjusting the blades of a ships propeller during service, its purpose being to make it possible for the device to be built into the hub or the shaft even though the adjusting forces are great.

In ships propellers, as opposed to aircraft propellers the device must be built into the hub and the shaft. The diameter of the shaft and above all that of the hub may then not become too great, as this would unfavourably inuence the efficiency of the propeller.

The invention provides accordingly a device for adjusting the propeller in which the servomotor is built into the shaft driving a propeller and rotates with that shaft, the servomotor having a piston actuated by a lubricating pressure means and actuating a screw gear at least partially lubricated by that pressure means which converts the linear motion of the servomotor piston into a rotary motion of a control shaft adjusting the propeller blades. The servomotor and the screw gear are to be combined in such a way that the piston runs both on a screw thread and on a longitudinal guiding, the thread and the guiding being respectively on the control shaft and the servomotor cylinder or vice versa. The longitudinal guiding need not necessarily be straight; but it may also be screw shaped and form with the screw thread a differential screw gear.

Several embodiments of the invention are illustrated diagrammatically in the accompanying drawings in which:

Fig. l is a horizontal section through the stern portion of a single screw vessel equipped with variable-pitch propeller and pitch control servomotor in the drive shaft;

Fig. 2 is a longitudinal section through selected portions of the servomotor control apparatus, servomotor drive shaft and propeller hub;

Fig. 3 is a transverse section through the -propeller hub;

Fig. 4 is a detail view partially in section on an enlarged scale of the propeller blade crank activating linkage;

Fig. 5 is an end View of the servomotor control apparatus;

Fig. 6 is a schematic illustration of an alternative control apparatus;

Fig. 7 is a longitudinal section illustrating an alternative embodiment of the servomotor proper;

Fig. 8 is a transverse section through the piston oi' the servomotor illustrated in Fig. 7;

Fig. 9 is a diagram of the forces of friction i gear and linkage;

Fig. 10 is an exterior view of the servomotor illustrated in Fig. 7 showing a method of pressure uid supply therefor;

Fig. 11 illustrates diagrammatically a further alternative embodiment of the servomotor and screw gear; and

Fig. 12 illustrates diagrammatically a final alternative embodiment of the servomotor and screw gear.

In Fig. 1 a marine propulsion plant is shown. The ship I is propelled by the engines 2 through the gear 3, 4, which drives the propeller 6 with its adjustable blades 1 through the propeller shaft 5. The adjustment of the blades 'I is effected by means of the servomotor 8, which may be connected to the bridge of the ship, for example through pipes 9 and I0, in a variety of ways not further represented in this figure. A thrust bearing Il is provided abaft the gear 3, 4. Instead of the servomotor 8 being constructed contained in the propeller shaft 5, it may also be arranged in the position designated l2 forward of the gear 3, 4, the purpose being to simplify the dismantling of the servomotor.

In Fig. 2 one form of complete installation of the servomotor 8 is shown partially in section with portions not requiring illustration omitted. The casing I3 of the servomotor 8 forms an intermediate part of the shafting 5 between the engine and the propeller. The servomotor piston I4 is axially displaced in the cylinder spaces I5, I6 by the pressure medium and is guided in a straight line by a feather I1 running in the groove I8. The piston I4 is further provided in itsbore I9 with a thread which engages with the thread of the adjusting shaft 20 in such way that, when the piston I4 is displaced from right to left, the shaft 28 turns in the direction of the arrow.

It will be understood that the straight screw I8 can be regarded as a thread of infinite pitch and could be replaced by a screw of some finite pitch, for example, the screw illustrated for the thread on shaft 20 provided only that shaft 20 is in turn provided with a thread of smaller pitch so that axial movement of piston I4 produces the same relative rotation between shaft 20 and casing I3.

Both the feather I1, the groove I8 and the thread in the bore I9 and on the shaft 20 are so accurately made and machined that they provide sealing between the pressure medium in the cylinder spaces I5 and I6.

The shaft 20 is supported at the ends of the spaces I6 and I6 ln bearings 2l provided with sealing means. AIt is coupled to the shaft 22 in thebore of the propeller shaft 5. The shaft 22 extends into the hub of the propeller 8 and is provided atits lefthand end with a disk 23 having slots 24 in which the sliding block 25 of eachof the blades 1 moves backwards and forwards. The sliding block 25 surrounds a ball 28 in the bore of which is supported .the pin 21 which forms the lever arm of the crank member 28-and serves for turning the blades 1px/The disk 23 is secured against free turning and attached to the tapered end of the shaft 22 by means of a key and a nut.

The collar portions of the cranks 28 surround pivots 29 of the blades 1 forming the three-bladed propeller 8 (Figs. 3, 4). They are pressed and keyed 'on the tapered pieces 3| by means of the nuts 39 and at the same time serve to support the pivots 29 and the blades 1 against the hub 32, in order to take the load caused by centrifugal forces. even when the pivot 29 is deflected, a spherical supporting surface 33 is provided on a supporting ring between the eye of the lever 28 and the bearing shell 34. This surface 33, however, might also bepresent on the eye of the crank 28 itself. The pivots 29 are supported in the bearings ,34 and 35 in the transverse wall 38. Provided in this are the openings 31 for the eyes of the cranks 28.

By' the advantageous arrangement of the cranks 28, which are directed towards the propeller shaft 5, the whole operating mechanism can be housed in the space 38 (Fig. 2), outside "the plane of the blades 1, so that a considerable strengthening of the hub 32 by means of the transverse wall 36'is made possible.

On the right-hand end of the adjusting shaft 20 (Fig, 2) is cut a gentle-pitch thread 48, and this engages with the thread in the sleeve 4I, which is secured against turning by the tongue 42. The'springv'43 is supported at one end on the sleeve 4I and at the other end on the spring plate 44 and loads the control member 45 with a force varying in accordance with the axial travel of the 4servomotor piston I4.

The control member 45, which controls the supply of pressure medium from the pipe 48 provided in the collar 41 surrounding the casing I3 of the servomotor 8, is loaded at its right-hand end, that is on the surface 48, by the pressure of the hydraulic or pneumatic transmission system 49, which can be set and changed at will by the man attending the servomotor 8, for instance by the steersman of the ship.

For the setting of the pressure in the system 49, the sender 50 is provided with an admission and discharge member I in the form of an actuating member, which is loaded on the one side by the pressure' of .the system 49 on its surface 52, and onlthe other side by the counter-pressure of thespring'53, which pressure serves to allow the blades and be set and changed at will. The loading of the spring 53 is donethrough the spindle 54 by means of the handwheel 55, the thread 58 of the spindle axially displacing the spring plate 51, which is secured against turning. The reduction gear 58 and the indicator 59 are operated by the spindle 54in such a way that the indicator 59 shows the setting of the propeller blades 1 (Fig. 5). The lever 68 serves for holding the spindle 54 from in its position.

If by the turning of the spindle 54 the spring plate 51 is displaced to the left, the spring 53 is loaded and displaces the actuating member 5I to the left. In this way the pressure medium supplied through the pipe 5| by the pressure medium pump or from some other source passes through the passage 82 into the transmission In order to obtain perfect supporting system 49. In the pipe 6I the available pressure is, for instance, 10 atm. gauge, and the pressure in the system 49 varies for the'whole range of adjustment of the propeller blades 1 between 1 and 9 atm. gauge. If the pressure in the system 49 is, for instance, 2 atm. gauge, this-pressure is increased by the above-mentioned supply of medium from the pipe 8|. The increased pressure in the transmission system 49 again displaces the member 5| to the right into the end position shown, as soon as it is high enough to balance the increased counter-pressure of the spring 53.

As a result of the higher pressure in the system 49, the surface 48 is also subjected to heavier loa/d and the control member 45 is displaced to the left. Pressure medium from the pipe 48 passes through the groove 83 in the collar 41 and through the passages 64, 85 and 66 into the cylinder I5, and moves the servomotor piston I4 to the left. The shaft turns in the direction of the arrow and adjusts the propeller blades 1. At the same time the return device 49 to 44 is set, in motion, in that the sleeve 4I moving to the right loads the spring 43. As a. result .the spring 43 is able to balance the increased pressure on the surface 48. The control member 45 is thus returned to its closed position, so that the pressure medium supply to the cylinder space I5 ceases.

During the displacement of the servomotor piston I4 to the left, the pressure medium from the cylinder I6 has flowed through the passages 81, 68 in the casing I3 into the discharge passages 89, 19 and into the space 12, and it passes from there through the passage 13 and the groove 14 into the discharge pipe 15 in the collar 41. The groove 11 in the collar 41 is connected to the discharge pipe 15 in order to prevent the pressure in the groove 83 altering the pressure in the system 49.

If the spindle 54 is turned in the opposite direction, so that the spring plate 51 moves to the right, the spring 53 is unloaded. The pressure of the system 49 on the surface 52 is then "great enough to displace the member 5| to the right. In this way communication is established between the system 49 and the discharge pipe 18 until the pressure in the system 49 diminishes enough to correspond to the lower loading of the spring 53.

This has the following :effect on the servomotor I4. As a result of the reduced pressure on the surface 48 of the control member 45, the pressure of the spring 43 becomes great enough to move the control member 45 to the right. The pressure medium from the pipe 48 passes through the passages, 68 and 81 into the cylinder space I8; that from the cylinder space I5 passes through the passages 86, 85, 1I into the space 12 and to the discharge pipe 15. The pressure medium forces the servomotor piston I4 to the right, the shaft -2|) turns in the direction opposite to the arrow, the pitch of the propeller blades 1 is decreased. At the same time the sleeve 4I moves to the left and unloads the spring 4I, whereby the member 45 is moved to the left into its closed position.

For the purpose of indicating the position of the servomotor piston I4 at the point of control, the

, following device is provided:

The surface 83 of the member 82 is under the pressure prevailing in the space 84, which is in communication through the passages 85, 86 and the annular groove 81 in the c ollar 41 with the hydraulic or pneumatic indication transmission system 88, to which one or more indicating devices 89 are connected. The pressuren medium from the pipe 46 is supplied by way of the groove 83 and the passages 84, 98 and 9| to the indication sender 82, which is connected to the return flow pipe 18 to 15 through the passage 92. When the indication transmission system 88 is long, it is preferable that it should be designed as a pneumatic system, so that the pipes 98 and 82 are separate from the pipes 46 and 18 and are connected to a source of compressed air.

The method of working consists in that if the servomotor piston I4 is displaced to the left, the pin 19 also moves to the left and relieves the spring 8|. The pressure on the surface 83 moves the indication sender 82 to the left, so that pressure medium from the space 84 and thus from the transmission system B8 can flow oif until equilibrium is established between this pressurev and the spring 8|, whereupon the indication sender" 82 comes into the closed position shown in the drawing.

If the servomotor piston moves to the right, communication is established by the indication member 82 between the pipe 46 up to the passage 9| and the space 84. A rise in the pressure in the space 84 and in the indication transmission system 88takes place until the member 82 arrives in its closed position and the higher counterpressure of the spring 8| is balanced. The pressure in the indication transmission system 88 changes, in accordance with the characteristic of the spring 8|, in proportion to the travel of the servomotor I4, and the indicating devices 89 may be designed as pressure gauges. It is preferable for their scales to show directly the pitch of the propeller blades 1 in degrees. The indication transmission system 88 has the advantage that it is possible for a pointer to be provided at several places.

The servomotor 8 with the sender, return and indicating devices described above, may of course be used not only for the adjustment of the propeller blades of ships or aircraft, but also for the adjustment of the blades of water turbines, pumps, fans and axial compressors as Well as for other purposes where a servomotor is required.

In Fig.v 6 the .segment 95 is moved by means of the handwheel 93 through the spindle 94. This segment turns about the axis 96 and carries withA it the double-armed lever 91 and the pointer 98.

this purpose the liner |82 is provided with one or more helical grooves |85, and these grooves are engaged by the correspondingly shaped projections |88 (Fig. 8) of the adjusting piston |83, which completely fill the grooves |85. When the servomotor piston |83 moves longitudinally, it thus turns at the same time about the axis of the shaft |84, which is provided with a longitudinal feather |81 engaging with the groove |88 of the servomotor piston |83.

As shown in Fig. 9, the angle of inclination 'y of the screw gear I9, 28 or |82, |83, its threads I9, 28 or |85, |88, can be approximately equal to or smaller than the sum of the angle of friction a of the threads I9, 28 or |85, |86 themselves, and an angle which corresponds to the static friction of the parts moving during adjustment. The angle is thus a. measure for the force Ra, which is necessary to bring out of their position of rest all the parts from th-e adjusting piston |4 or |83 on, that is to say the adjusting shaft 28 or |84 the linkage, etc., up to and including the adjustable blades`1 (Fig. 2), it being necessary to overcome not only the bearing friction at full load and the friction in the joints, etc., but also the resistance of the pressure medium to be displaced in the auxiliary motor 3 or |2.

The resultant of the hydraulic forces acting on the adjustable 'blades produces a torque which would cause the blades to turn if the inclination of the thread of the screw gear were not suitably designed to withstand this. However, as such a torque must overcome considerable frictional forces, in particular in the bearings of the blades 1 themselves, as a .result of loading by hydrodynamic and centrifugal forces, it is not nesessary for the screw gear I9, 28 or |82, |83 itself to be self-locking. It is only the abovementioned friction R3 from the blades to the adjusting piston I4 or |83 and the frictions R1 and R2 of the screw gear itsel'f which need to give a partly or ccmpletely self-locking effect.

The propeller shaft 5 has to transmit a con.- siderable torque. As the casing |8|, as an intermediate shafting piece, is submitted to torsion in accordance with the magnitude of the torque of the propeller shaft, a liner |82 is provided which it separate from the casing |8|. The liner |82 is only carried round by the tongues' |89 on the ange |I8, which fit into the gaps |II. Thi; offers the advantage that the torsion of casing |8| cannot make itself felt in the liner |82 and any sticking of the projections |86 in the grooves |85, in which they must slide without any play on account of the sealing of piston |83, is impossible.

The double-armed lever 91 is coupled on one side y to the spring plate 51, and on the other side to a piston 99. The piston 99 is in communication through the pipe |88 with the system 49 and has the same pressure surface as the member 5|. The purpose of this is to balance the pressure of the spring 53 on the lever 91 so that th adjusting force to be employed on the spindle 94 has only to overcome the friction in the transmission system of the sender.

Instead of the bore I9 of the servomotor'piston I4 and the shaft 28 in Fig. 2 being provided with -a steep-pitch thread, either the cylinder |8| of the servomotor I2 (Fig. 7) itself or preferably the liner |82 in the cylinder |8| may form with the adjusting piston |83 a screw gear, which transforms the motion of the piston |83 in a direction parallel to the axis of the shaft into a rotary motion of the adjusting shaft |84. For

The shaft part |84 is connected through the sliding coupling ||2 to the adjusting shaft 22, which is supported in the shaft 5 and rotates the disc 23 (Fig. 2) for turning the propeller blades 1. This coupling is so arranged that the part' Il! can slide in part I I3 in an axial direction, in order to prevent any change of length in the adjusting.

shaft 22 from exerting an effect upon the bearings and sealing of part |84.

The liner |82 has passages ||4 and ||5 communicating with passages, which open into the A groovesof the collar ||6 and are connected to the openings of the slide valve I I1. The valve I I1 controls the supply of pressure oil from pipe ||8 and its discharge through pipe vI |9 to and from the cylinder spaces to the left and right of piston |83.

The right-hand end of the adjusting shaft |84 ls provided with a thread |28 and surrounded by the cross-piece I2| with the corresponding counter-thread. The bolts |22 in the bores |23 of the flanges I I and |24 connect the cross-piece |2| to the sleeve |25, which turns in the stationary adjusting ring |26. The adjusting ring |26 is provided with two pins which support the levers |21 on both sides of the stationary ring |26, these levers being connected by means of the bolts |28 and |29. The valve ||1 is linked to the bolt |23 and the rod is connected to the bolt |29, this rod representing for instance the final member of a linkage from the adjusting lever on the bridge of the ship to the valve ||1.

The method of operation is clear from the drawing. The rod |30 first displaces the valve ||1 by the turning of the lever |21, so thatv the pressure medium acting upon one or the other side of the piston |03 brings about a displacement of this piston. The cross-piece 2| and the sleeve |25 are meanwhile displaced in the same direction as the piston |03 as a result of the turning of the shaft |04, and the member I|'| is returned to the middle position.

For a ship's propeller which must be adjusted both for motion ahead and astern, the position of the piston |03 shown in the drawing corresponds to the neutral position of the blades 1 between ahead and astern motion. In the end positions of the piston |03 the maximum blade adjustment for the one or the other direction of motion is reached. In the case of propellers whose blades are only to be turned between positions of minimum and maximum adjustment, as for example in aircraft, the end positie-ns of the piston |03 would correspond to the extreme adjustments. :n:

If the servomotor |2 were employed within the shafting, the flange |24 would be provided on the shaft piece on the side of the propelling engine; this is shown in the drawing by the chain-dotted line.

Arranged below the control valve ||1 in Fig. l0 is the gearwheel pump I3| which is driven direct from the shafting 5 by means of a chain |32. The pump supplies the pressure medium for adjusting the piston |03.

The use of an auxiliary motor built into the propeller shaft with the screw gear as shown in Fig. 2 or in Figs. 7, 8, and 10 offers a very good transmission of force. In this; way the advantage is obtained that the cylinder of the servomotor may have a much smaller diameter than inthe arrangements hitherto known. As a result the servomotor may also be built into the propeller shaft at a much smaller distance from the stern tube, so that not only the length of the hollowbored propeller shaft but also that of the adjusting shaft can be kept small.

In Fig. 11 the piston |34, ukethepistonu,

Fig. :12, is axially guided in the casing V|33 by the groove |35 and the longitudinal vkey. |33. The adjusting shaft |31 is connectedto the piston |34 through the screw gear |38. Thelscrewgear is designed as a steep-pitch thread, whose pitch, however, is such that, when the piston |34 is moved from one end position to the other, the shaft |31 performs several revolutions, in contrast to the designs shown in Figs. 2 and 3.

For this reason the shaft |31 is provided at its end situated in the hub 6 with a further screw gear i |39, which is designed as a gentle-pitch thread. The cross-piece has a corresponding internal thread, so that the rotation of the shaft |31 is converted into an axial motion of the linkage |40, |4| for adjusting the blades 1. This offers the advantage that the manufacture of the servo- 8 motor |33, |38 is simpler than that of the servomotor I3, 20 in Fig. 2, because the manufacture of the steep-pitch thread |38 does not require any special devices but only an ordinary lathe. and above all because the diameter of the cylinder |33 may be smaller than that of the cylinder I3.

The arrangement of the screw 'gear |39 in the hub 6 has the advantage that only the linkage |40, |4| is axially displaced in the hub |38 and no displacement of the shaft |31 takes place. As a result, when the shaft |31 turns, the volume of the hub space does not change, and even at low temperature and with viscous oil neither excessive nor insufficient pressures can present themselves in the hub.

The adjustment of the servomotor piston |34 takes place, as in Figs. 2 and '1, by pressure medium which is controlled by the necessary control member and is supplied or led off, according to the direction of adjustment of the piston |34, through the passages |42 and |43. The support ing bearing |44 serves to take the axial thrust transmitted to the shaft |31 through the linkage |40, |4| by the hydraulic forces acting on blades 1, this thrust being partly balanced by the loading of the piston |34 by the pressure medium.

The servomotor |45 in Fig. 12 also has a gear |38, as in Fig. l1, between the piston |48 and the adjusting shaft |41. On the other hand the screw gear |39 and the supporting bearing |44 in Fig. 11 are replaced by the screw gears |48 and |49, which are likewise designed as gentle-pitch single or multiple thread gears and are preferably self-locking. When the shaft |41 turns, thegear |49 held rm by the end wall |50 produces at the same time an axial displacement of the shaft |41, so that the gear |48 is also displaced. Moreover, the gear |48 produces a further displacement of the adjusting rod |5|, which is supportedin the propeller shaft 5 and secured against turning. The axial motion of the rod |5| is then the sum of both displacements. This has the advantage that the length of the thread in each section |48, |49 of the screw gear can be kept small and a special supporting bearing can be dispensed with. At the same time the length of the casing and thus the length of the intermediate shafting piece can be kept smaller than the length of the casing |3 in Fig. 2.

I claim:

1. In the propelling plant of a vessel having a variable pitch propeller, a propeller driving shaft, a propeller hub carried by said shaft, adjustable propeller blades pivotally mounted on said hub, a blade adjustment actuating shaft extending axially within and mounted rotatably in relation to said driving shaft, mechanical transmission means operatively connecting said actuating ,shaft to each of said blades, a hydraulic servomotor cylinder extending axially within and car ried by said driving shaft and'disposed coaxially about said actuating shaft, a cylindrical piston fitted in said cylinder about said actuating shaft. fiuid conduit means leading into said cylinder on both Sides of said piston, a source of fluid under pressure connectable through said conduit means to either side of said piston at will, and motion transforming means for transforming linear motion of said piston into rotary motion of said actuating shaft comprising a screw gear having helical guide lmeans within said cylinder engaging the piston to one of said shafts and additional guide means within said cylinder engaging the piston to the other of said shafts, the pitches of said screw gear being selected to make the adjustment oi' the blades in combination with said mechanical transmission means self-locking and Y at least the ends of the engaging surfaces of said screw gear being exposed to the fluid under pressure when said fluid actuates said piston on either side thereof.

2. -The combination of claim y1 in which the mechanical transmission means comprises a second screw gear operated by the actuating shaft outside the cylinder for converting the rotary motion of said actuating shaft relative to the driving shaft into an axial vmotion relative to said driving shaft and asystem of linkage for utilizing said axial motion to adjust the blades.

3. The combination of claim 1 in which the mechanical transmission means comprises a second screw gear operated by the actuating shaft outside the cylinder for converting the rotary motion of said actuating shaft relative to the driving shaft into an axial motion relative to said driving shaft and a system of linkage for utilizing said axial motion to adjust the blades and the pitches of said second screw gear are selected in combination with the pitches of the first screw gear to make the adjustment of the blades selflocking.

EDOUARD A'I'IESLANDER.

REFERENCES CITED The following references are of record in. the file of this patent:

10 UNITED STATES PATENTS Number Name Date 547,459 Seymour Oct. 8, 1895 617,633 Brinkmann Jan. 10, 1899 1,806,083 Roberts May 19, 1931 1,828,965 Fuller et al Oct. 27, 1931 1,878,358 Yates Sept. 20, 1932 1,925,566 Ring Mar. 27, 1934 1,967,302 Gannett July 24, 1934 2,028,463 McDougall Jan. 21, 1936 2,210,009 Ruths et al Aug. 6, 1940 2,279,301 Colley et al. Apr. 14, 1942 2,280,714 Martin Apr. 21, 1942 2,355,039 Eves Aug. 1, 1944 FOREIGN PATENTS Number Country Date 27,972 Denmark July 13, 1920 789,794 France Nov. 6, 1935 217,669 Switzerland Apr. 16, 1942 OTHER REFERENCES Two Swiss Propeller Developments, The Marine Engineer, February 1942, pages 30 and 31. 

